fishery which has a limited ability to withstand additional 

 losses through angler harvest. Restrictive regulations, imposed 

 throughout the Blackfoot River in 1988 due to the effects of the 

 current drought, provide a unique opportunity to evaluate the 

 potential of this management tool. Evaluating this regulation, 

 which reduces the creel limit to two fish, none exceeding 14 

 inches, will help us determine whether the fishery can be 

 enhanced by reducing mortality due to anglers. 



Although brown trout comprised a significant portion of the 

 catch (38%) in the Scotty Brown Bridge Section, the majority of 

 the fish were observed staging near spawning tributaries and may 

 not have been residents of this section. A springtime estimate 

 will provide a more accurate assessment of resident brown trout 

 abundance in this segment of the Blackfoot River. 



Reach 5: Mouth to Belmont Creek 



(RM to 21.9) 



Physical characteristics of reach 5 are similar to reach 4, 

 except that the Blackfoot River grows in size due to the inputs 

 of several major tributaries. The reach break at the mouth of 

 Belmont Creek was chosen because of changes in characteristics of 

 the fishery in this vicinity. During 1988, no population 

 estimates were obtained in this reach due to poor sampling 

 efficiencies during the fall. Survey runs of adult trout 

 populations were made from River Bend FAS to Whitaker Bridge and 

 in the Johnsrud Section. Population estimates were previously 

 conducted six times between 1980 and 1985 in the Johnsrud 

 Section. Sampling of the Johnsrud Section is scheduled for 

 spring/summer 1989 since it was not accomplished during this 

 inventory as planned. 



The density of rainbow trout increases significantly in this 

 segment of the Blackfoot River. Similar to reach 4, rainbow 

 trout YOY were abundant in this reach, but unlike the upstream 

 fishery, these large numbers of juveniles appear to carry over 

 into very high densities of subsequent age classes. Estimated 

 numbers of rainbow trout from 4.0 to 10.9 inches (over 500/1000 

 ft) in the Johnsrud Section are the higher than in any other 

 western Montana rainbow trout fishery. This exceptionally high 

 density of small fish not only indicates that recruitment is 

 excellent, but that juvenile fish missing in the upstream reach 

 may be moving to this segment of river. 



The density of larger trout in the Johnsrud Section, 

 however, is lower than in most of the larger rivers of western 

 Montana. Trout growth is relatively slow in the lower Blackfoot 

 River, but the low numbers of trout larger than 12.0 inches in 

 this reach appear to be primarily due to extremely heavy fishing 

 pressure. The 1984-85 statewide fishing pressure survey 

 estimated 23,082 fisherman trips on the Blackfoot River between 



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